Saw blade clamping arrangement for a power tool

ABSTRACT

A saw blade clamping arrangement particularly for power reciprocating saws and similar tools having a reciprocating shaft connected to a cutting member includes a locking member and a locating pin which cooperates to prevent inadvertent removal of the saw blade. The saw blade clamping arrangement further includes a support member carried by the drive shaft for movement therewith. The support member at least partially defines a longitudinal slot for receiving the saw blade. The locating pin extends into the longitudinal slot and is adapted for partial insertion into the aperture from a first side of the saw blade. The locking member, which in the preferred embodiment is a spherical bearing, is operative for selectively engaging the saw blade with the drive shaft. The locking member is movable to a locking position in which the locking member is partially inserted into the aperture from a second side of the saw blade.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part application of U.S. Ser. No. 08/881,091filed Jun. 24, 1997, which is a continuation-in-part application of U.S.Ser. No. 08/744,023 filed Nov. 5, 1996, now U.S. Pat. No. 5,794,352which is a continuation-in-part application of U.S. Ser. No. 08/504,050,filed Jun. 9, 1995 (now U.S. Pat. No. 5,647,133, issued Jul. 15, 1997).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to power tools. In particular,the present invention relates to a saw blade clamping arrangement for apower tool having a saw blade mounted for reciprocating cutting motion.

2. Discussion

Power reciprocating saws include jigsaws and other reciprocating sawsgenerally referred to in the trade as "recip" saws. These sawsincorporate reciprocating shafts for driving generally linear saw bladesalong a predetermined path so as to provide one of a rectilinear ororbital cutting action.

In a conventional manner, the saw blades used with such power tools areattached to the reciprocating drive shafts through a blade holder havinga slot for receiving the saw blade and a set screw which is received ina hole in the blade. The blade is clamped in place relative to thereciprocating drive shaft through tightening of the set screw. Whilethis manner of saw blade attachment has proven to be generallysatisfactory and commercially successful, it is not without inherentdisadvantages.

For example, power reciprocating saws are subject to high vibrationforces during operation which frequently result in loosening of the setscrew. If the set screw does not remain sufficiently tightened, the sawblade may become disengaged from the drive shaft. An additionaldisadvantage with the conventional mounting of saw blades toreciprocating drive shafts relates to an inability to quickly and easilyremove saw blades which become worn or fractured. Because it is oftendesirable to cut a workpiece with minimum material loss, it is desirableto correspondingly minimize the saw blade thickness. As a result,breakage due to the forces encountered during typical use is not anuncommon occurrence. This potential frequency of blade changing makesthe ease and rapidity of such action desirable. A further disadvantageof conventional blade mounting arrangements is the necessity for aseparate tool such as a wrench for fixation and removal of the sawblade.

Many previous attempts have been made to overcome the disadvantagesassociated with the above-described conventional mounting of saw bladesthrough elimination of the use of a set screw. One example of such a sawblade mounting arrangement is shown in U.S. Pat. No. 5,322,302. The sawblade mounting arrangement described in this patent includes a mountingbody which urges a clamping sphere through the biasing force of a springinto clamping engagement with a saw blade. Removal of the saw blade isfacilitated through actuation of a lever which serves to overcome thebiasing force exerted by the spring. Operation of this device requires afirst of the operator's hands to actuate the lever and a second of theoperator's hands for removal or installation of the saw blade. In otherwords, the actuating lever of this device is not movable to a stable,non-clamping position and necessarily requires two-handed operation--anaction which is not always convenient.

Other previous attempts to secure saw blades to a reciprocating driveshaft of a power tool without the conventional use of a set screw areshown in U.S. Pat. Nos. 3,542,097; 3,823,473; 4,020,555; 4,106,181;4,441,255; 4,594,781; 4,470,196; 4,528,753; 4,601,477; 4,648,182;5,113,565; 5,263,972; and 5,324,052.

In general, each of the devices shown in these patents represents anattempt to overcome one or more of the disadvantages associated withconventional set screw attachment of a saw blade to a reciprocatingdrive shaft, including but not limited to the disadvantages discussedabove. However, all of these devices are subject to further refinementand improvement. For example, many of the devices, including U.S. Pat.No. 5,322,302, disadvantageously require two-handed operation.Additionally, most of the devices shown in these patents are complicatedand expensive to manufacture and assemble as a result of a constructionincluding many separate parts. Further, operation of many of the priordevices requires application of force which is often significant forsecuring the saw blade in place and loosening of the blade forseparation from the drive shaft. Achieving a sufficient force oftenrequires the use of a wrench or other tool. Other disadvantagesassociated with these prior devices include an inability to cooperatewith conventionally shaped saw blades.

SUMMARY OF THE INVENTION

The present invention comprises an improvement over prior known blademounting arrangements for power tools, including those disclosed in theaforementioned patents. More particularly, the present inventionprovides a new and improved saw blade mounting arrangement for a powerreciprocating saw which includes a release lever operative to permitquick and easy installation and removal of a saw blade. In each of thetwo preferred embodiments which will be described in detail below, therelease lever is pivotally mounted for movement between two stablepositions. Further in the preferred embodiments, the release lever isnot interconnected with the drive shaft for reciprocating movementtherewith.

Rather, the release lever is pivotally attached to the housing, therebyreducing the mass carried by the reciprocating shaft. Advantageously,the present invention provides a power reciprocating saw in which thesaw blade can be mounted in place and detached using only a single hand.Additionally, the present invention provides a saw blade mountingarrangement for a power reciprocating saw of simple construction whichis relatively inexpensive to manufacture and assemble. Furthermore, thepresent invention provides a blade mounting arrangement which canaccommodate conventional saw blades of various constructions and whichcan hold the saw blade in place without the use of set screws andwithout the need to employ any other form of a tool. Still yet, thepresent invention provides a blade mounting arrangement having a designwhich protects its components from excessive wear and premature failure.

The present invention provides a saw blade clamping arrangement for apower tool of the type including a housing, a drive shaft mounted forreciprocating motion relative to the housing, and a saw blade releasablyinterconnected with the drive shaft. The saw blade clamping arrangementincludes a biasing member and an actuation member. The biasing member isinterconnected to the drive shaft for exerting a biasing force to retainoperative connection between the saw blade and the drive shaft. Theactuation member is selectively moveable between a first position and asecond position. The first position permits the biasing force of thebiasing member to retain the operating connection between the saw bladeand the drive shaft. The second position causes the actuation member toovercome the biasing force, thereby permitting removal of the saw bladefrom the drive shaft.

In one form, the present invention provides a power reciprocating sawhaving a gear case housing and a drive shaft mounted to thereciprocating saw for reciprocating motion relative to the gear casehousing. A saw blade is releasably interconnected to the drive shaft formovement therewith. The power reciprocating saw further includes aclamping arrangement for mounting the saw blade to the drive shaft whichincludes a clamp support member, a spring clamp member and a releaselever. The clamp support member is attached to the drive shaft formovement therewith. The spring clamp member is supported by the clampsupport member and operates to retain the saw blade against the driveshaft. The release lever is pivotally attached to the housing forpivotal movement in a first direction about a pivot axis from a firststable position to a second stable position. In the first stableposition, the spring clamp member exerts a biasing force to retain thesaw blade in operative engagement with the drive shaft. In the secondstable position, the release lever operates to overcome the biasingforce of the spring clamp member to permit removal of the saw blade fromthe drive shaft.

In another form, the present invention provides a power reciprocatingsaw having a gear case housing and a drive shaft mounted to thereciprocating saw for reciprocating motion relative to the gear casehousing. A saw blade is releasably interconnected to the drive shaft formovement therewith. The power reciprocating saw further includes aclamping arrangement for mounting the saw blade to the drive shaft. Theclamping arrangement preferably includes a clamp support member, alocking member, a spring clamp member and a release lever. The clampsupport member is interconnected with the drive shaft for movementtherewith and includes a longitudinal slot for receiving the saw bladeand a transversely disposed aperture intersecting the longitudinal slot.The locking member is selectively engageable with the saw blade tooperatively interconnect the saw blade to the drive shaft and extends atleast partially into the transversely disposed aperture of the clampsupport member. The spring clamp member is supported by the clampsupport member and biases the locking member into engagement with thesaw blade. The release lever is pivotally attached to the housing forpivotal movement between a first position in which the locking member isengaged with the saw blade and a second position in which the lockingmember is disengaged from the saw blade.

In yet another form, the present invention provides a saw blade clampingarrangement for a power tool including a housing, a drive shaft mountedfor reciprocating motion in a longitudinal direction relative to thehousing, and a saw blade releasably interconnected with the drive shaft.The saw blade clamping arrangement includes a support member carried bythe drive shaft for movement therewith. The support member at leastpartially defines a longitudinal slot for receiving the saw blade. Thesaw blade clamping arrangement additionally includes a locating pinextending into the longitudinal slot and adapted for partial insertioninto the aperture from a first side of the saw blade. The saw bladeclamping arrangement further includes a locking member operative forselectively engaging the saw blade with the drive shaft. The lockingmember is movable to a locking position in which the locking member ispartially inserted into the aperture from a second side of the sawblade. The locking member and the locating pin cooperate to preventinadvertent removal of the saw blade from the longitudinal slot.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will becomeapparent from a reading of the following detailed description of thepreferred embodiments which makes reference to the drawings of which:

FIG. 1 is a side elevational view of a reciprocating saw incorporating asaw blade clamping arrangement constructed in accordance with theteachings of a first preferred embodiment of the present invention;

FIG. 2 is an exploded perspective view of the saw blade clampingarrangement of the present invention;

FIG. 3 is an enlarged side view of the clamp support member shown inFIG. 2;

FIG. 4 is an enlarged end view of the clamp support member;

FIG. 5 is an enlarged side view of the clamp spring member shown in FIG.2;

FIG. 6 is an enlarged end view of the clamp spring member;

FIG. 7 is a partial side view of the saw blade clamping arrangement ofFIG. 1, illustrating interconnection of the drive shaft with aconventional saw blade;

FIG. 8 is a partial cross-sectional view of the keyless saw blade clampof FIG. 1 taken along the line 8--8 of FIG. 1 illustrated with the endplate of FIG. 2 removed for purposes of clarity;

FIG. 9 is a partial view of a mounting portion of a first alternativesaw blade configuration acceptable for use with the saw blade clampingarrangement of the present invention;

FIG. 10 is a partial view of a mounting portion of a second alternativesaw blade configuration acceptable for use with the keyless saw bladeclamping arrangement of the present invention;

FIG. 11 is a cross-sectional view of the clamping assembly of FIG. 1taken along the line 11--11 of FIG. 1, illustrating the release leverrotated to a first stable position in which the clamp spring member ofthe clamping assembly biases the saw blade into operative connectionwith the drive shaft;

FIG. 12 is a cross-sectional view similar to that shown in FIG. 11,illustrating the release lever in a second stable position in which theclamp spring member is displaced from the saw blade by the releaselever, thereby permitting the saw blade to be easily removed from theclamp assembly;

FIG. 13 is an exploded view of a saw blade clamping arrangementconstructed in accordance with the teachings of a second preferredembodiment of the present invention and a portion of a reciprocatingsaw;

FIG. 14 is an enlarged side view of the clamp support member of thesecond preferred embodiment shown in FIG. 13;

FIG. 15 is a cross-sectional view taken along the line 15--15 of FIG.14;

FIG. 16 is an enlarged side view of the locking pin member of the secondembodiment shown in FIG. 13;

FIG. 17 is an enlarged side view of the spring clamp member of thesecond embodiment shown in FIG. 13;

FIG. 18 is a partial cross-sectional view of the saw blade clampingarrangement of FIG. 13, illustrating the lever rotated to a firstposition in which the locking pin member is displaced from the slotwhich receives the saw blade, thereby permitting the saw blade to beeasily removed or inserted from the clamp support member;

FIG. 19 is a partial cross-sectional view similar to that shown in FIG.18, illustrating the release lever in a second position in which theclamp spring member biases the locking pin member into a locked positionfor retaining the saw blade within the slot;

FIG. 20 is a side view of a portion of a reciprocating saw illustratedto include a partial cross-sectional view of a saw blade clampingarrangement constructed in accordance with the teachings of a thirdpreferred embodiment of the present invention;

FIG. 21 is an end view of the reciprocating saw of FIG. 20, illustratingthe saw blade clamping arrangement in a clamped position;

FIG. 22 is an end view similar to FIG. 21, illustrating the saw bladeclamping arrangement in a release position;

FIG. 23 is an enlarged side view of the saw blade clamping arrangementof FIG. 20 shown removed from the reciprocating saw for purposes ofillustration;

FIG. 24 is an end view of the saw blade clamping arrangement of FIG. 22;

FIG. 25 is a top view of the clamp support member of FIG. 24;

FIG. 26 is a top view of the clamp support member of FIG. 24;

FIG. 27 is a side view of the slider member of FIG. 24;

FIG. 28 is a cross-sectional view taken along the line 28--28 of FIG.27;

FIG. 29 is an end view of the collar of FIG. 24;

FIG. 30 is a side view of the collar of FIG. 24;

FIG. 31 is a cross-sectional view taken along the line 31--31 of FIG.30;

FIG. 32A is a perspective view of a first end of an outer member of analternative collar for use with saw blade clamping arrangement of thethird preferred embodiment of the present invention;

FIG. 32B is a perspective view of a second end of the outer member;

FIG. 33A is a perspective view of a first end of an inner memberintended to cooperate with the outer member of FIG. 30;

FIG. 33B is a perspective view of a second end of the inner member; and

FIG. 34 is a view similar to FIG. 26, enlarged and illustrating the sawblade held in position within the clamp by the bearing and the locatingpin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an improved saw blade clampingarrangement for a power tool. While shown throughout the drawings invarious embodiments for a saw blade clamping arrangement specificallyadapted for a reciprocating saw, those skilled in the art willappreciate that the invention is not so limited in scope. In thisregard, the teachings of the present invention will be understood to bereadily adaptable for use with any power tool incorporating one or morereciprocating cutting members (e.g., reciprocating saws, jig saws,various surgical saws and culinary knives, etc.).

Turning generally to the drawings in which identical or equivalentelements have been denoted with like reference numerals, andspecifically to FIGS. 1 through 12 thereof, a first preferred embodimentof an exemplary power tool is shown. The exemplary power tool embodiesthe teachings of the present invention and is illustrated in FIG. 1 as apower reciprocating saw which has been identified generally at referencenumeral 10. In a conventional manner, power reciprocating saw 10 ispowered by a motor (not shown) that is actuated by a trigger switch 12.The delivery of electrical energy to the motor through a power cord(partially shown at 14) is controlled by trigger switch 12.

In the exemplary embodiment illustrated, power tool 10 is shown toinclude a handle portion 16 which carries trigger switch 12. Power tool10 is also shown to include a housing 18 that includes a centrallylocated motor housing portion 20 and a forwardly located gear casehousing portion 22. As shown most clearly in FIG. 2, gear case housingportion 22 is formed to include a front face 24 having a generallyrectangular aperture 26 which defines the opening of a longitudinallyextending drive shaft channel 28.

Power tool 10 further includes a drive shaft 30 partially extendingwithin drive shaft channel 28 and operatively connected with a drivemechanism (not shown) housed within gear case housing portion 22. Thisinterconnection between the drive mechanism and drive shaft 30 can be inany manner well known in the art. Drive shaft 30 is mounted forreciprocating motion generally along the longitudinal axis defined bypower tool 10.

As shown in FIGS. 1 and 2, the housing 18 includes first and secondforwardly extending sidewall members 32 and 34 interconnected with gearcase housing portion 22. In the first preferred embodiment, first andsecond forwardly extending side wall members 32 and 34 are integrallyformed with gear case housing 22 and are constructed of aluminum,magnesium or other suitable lightweight metal. The particularconfiguration and function of first and second forwardly extendingsidewall members 32 and 34 will be described in detail below.

Drive shaft 30 is adapted to cooperate with a cutting member such as asaw blade 38 for driving the saw blade 38 back and forth in a cuttingmotion along a rectilinear path. In this regard, reciprocating driveshaft 30 is formed to include a transversely extending aperture 40 forreceiving a drive pin 42 (shown in FIG. 7). An interference fit retainsdrive pin 42 within aperture 40. The saw blade construction shown inFIGS. 1 and 7 conventionally includes a forwardly located cuttingportion 44 integrally formed with a rearwardly located mounting portion46. In a manner well known in the art, an aperture 48 formed in mountingportion 46 of saw blade 38 receives drive pin 42 when saw blade 38 ismounted to reciprocating drive shaft 30. The exposed end of drive pin 42extends from a first side wall 52 (shown in FIG. 8) of reciprocatingshaft 30 in a dimension approximately equivalent to the thickness of sawblade 38.

Power tool 10 of the present invention further includes a clampingarrangement 56 for releasably maintaining saw blade 38 in operativeconnection with reciprocating drive shaft 30. Clamping arrangement 56 isshown throughout the drawings to include a clamp support member 58, abiasing member 60, and a actuation member 62. The remainder of thisdetailed description of the first preferred embodiment will be primarilydirected to the construction and operation of clamping arrangement 56which is the focus of the present invention.

Referring specifically to FIGS. 3 and 4, the construction and operationof the clamp support member 58 will be described. In the exemplaryembodiment shown throughout the drawings, clamp support member 58 isillustrated as a separate element which is adapted to be interconnectedwith reciprocating drive shaft 30 for movement therewith. However, itwill be appreciated by those skilled in the art that clamp supportmember 58 and drive shaft 30 may alternatively be integrally formed as asingle component. Clamp support member 58 is unitarily constructed of ahardened steel or other suitable material. Interconnection between clampsupport members 58 and drive shaft 30 is established through a roll pin68 in interference fit engagement with a transversely extending aperture70 passing through clamp support member 58 and a corresponding aperture72 disposed in reciprocating drive shaft 30.

Clamp support member 58 includes a main body portion 73 which partiallydefines a longitudinally extending channel 74 sized to receivereciprocating drive shaft 30. More particularly, the longitudinalchannel 74 is defined by an inner wall 75 and by first and secondopposing side walls 76 and 78 which each terminate at end walls 80 and82, respectively. Inner wall 75 is concavely curved to receive a secondside wall 79 of reciprocating drive shaft 30. In the first preferredembodiment, a first side wall 52 of reciprocating drive shaft 30 isadapted to sit flush with end walls 80 and 82 (as shown in FIGS. 11 and12). End walls 80 and 82 cooperate with first side wall 52 to provide asurface against which saw blade 38 is disposed when operativelyconnected with a power tool 10.

Adjacent an upper surface 86, clamp support member 58 is formed tointegrally include an L-shaped flange 88 which partially defines achannel 90 for receiving an upper surface 94 of saw blade 38. Adjacent alower surface 96, clamp support member 58 includes an outwardlyextending portion 98 adapted to abut a lower surface 100 of saw blade38. Upper surface 86 of clamp support member 58 includes a pair ofspaced, upwardly extending flange portions 102 and 104. As will beappreciated below, flange portions 102 and 104 cooperate to limitlongitudinal movement of biasing member 60. A second transverselyextending channel 108 is partially defined between the main body portion73 of clamp support member 58 and a downwardly extending portion 110 ofa rear wall 112 of clamp support 58. Channel 108 is open along a bottomside.

Referring specifically to FIG. 6, the biasing member of the presentinvention is preferably illustrated as a spring clamp member 60. Springclamp member 60 is adapted to be directly carried by clamp supportmember 58 for movement with reciprocating drive shaft 30. Spring clampmember 60 is generally C-shaped and is integrally formed of a resilientmetal or other suitable material to include a curvilinear centralportion 120 and first and second ends 122 and 124. In one application,spring clamp member 60 is constructed of 0.050 inch steel. A side viewof clamp spring member 60 is shown in FIG. 6 in a substantially unloadedcondition. An aperture 125 passes through central portion 120 which isadapted to accept an end of drive pin 42 when a saw blade is not inclamping arrangement 56.

Clamp spring member 60 further includes generally linear upper and lowersegments 126 and 128 integrally attached to opposite ends of curvilinearcentral portion 120. Upper and lower segments 126 and 128 are disposedgenerally transverse to curvilinear central portion 120 and cooperatewith the curvilinear central portion 120 to partially define alongitudinally extending opening 130 for receiving a portion of clampsupport member 58 and reciprocal drive shaft 30.

Spring clamp member 60 is further shown to include a retaining portion132 adjacent second end 124 which is adapted to be constrained withinlongitudinal channel 108 of clamp support member 58. Spring clamp member60 further integrally includes a spring tab portion 136 adjacent firstend 122 which extends upwardly relative to upper segment 126 and isangled slightly rearwardly in the direction of curvilinear centralportion 120. Spring tab portion 136 is free from direct constraint withrespect to clamp support member 58.

When assembled and in clamping engagement with drive shaft 30 and sawblade 38, lower segment 128 of spring clamp member 60 is positionedadjacent bottom surface 96 of clamp support member 58. In an unloadedcondition, upper segment 126 of spring clamp member 60 is arranged to bepositioned substantially adjacent upper surface 86 of clamp supportmember 58. As discussed above, longitudinal translation of spring clampmember 60 is limited by flange portions 102 and 104 of clamp supportmember 58.

Curvilinear central portion 120 includes a lower, outwardly curvedsegment 139 which accommodates saw blade 38 and an upper, outwardlycurved segment 140. Curvilinear central portion 120 further includes aninwardly curved central portion 142 arranged to directly contact sawblade 38. It will be appreciated by those skilled in the art that theparticular construction of spring clamp 60 is subject to modificationwithout departing from the scope of the present invention. Anyconstruction will be suitable which incorporates a portion for fixationto clamp support member 58, a portion for directly biasing saw blade 38and a displaceable free end.

While in a clamping position such as that shown in FIG. 11, clamp springmember 60 functions to exert a biasing force against saw blade 38through contact of central portion 142 and saw blade 38. The biasingforce serves to retain saw blade 38 in operative connection withreciprocating drive shaft 30 by preventing saw blade 38 from movingtransversely with respect to drive shaft 30.

It will be appreciated by those skilled in the art that clampingarrangement 56 of the present invention is able to accommodate sawblades of various configurations without modification. By way of exampleand not of limitation, two alternative saw blade constructions suitablefor use with clamping arrangement 56 are illustrated in FIGS. 9 and 10.Referring to FIG. 9, a first alternative saw blade 38' includes agenerally rectangular mounting portion 46' formed with an aperture 48'sized to receive drive pin 42. In FIG. 10, a second alternative sawblade 38" is shown to include an aperture 48" and a longitudinallyextending slot 144. Any of a number of other known saw bladeconstructions may be releasably interconnected to drive shaft 30 throughclamping arrangement 56 of the present invention.

As shown throughout the drawings, actuation member of the presentinvention is preferably illustrated as a release lever 62 operative toovercome the biasing force of spring clamp member 60 and therebyfacilitate removal and replacement of saw blade 38. In the exemplaryembodiment illustrated, release lever 62 is mounted for pivotal movementbetween a first stable position or clamped position (shown in FIG. 11)and a second stable position or unclamped position (shown in FIG. 12).Significantly, when release lever 62 is in its first stable position, itis spaced apart from spring clamp member 60 permitting release lever 62to remain longitudinally fixed with respect to housing 18. Thus, releaselever 62 remains relatively stationary as reciprocating drive shaft 30operates, thereby reducing the weight translated back and forth by driveshaft 30 and also reducing attendant vibration forces.

To facilitate pivotal mounting of release lever 62, power tool 10further includes an end plate 150 interconnected with first and secondforwardly extending sidewall members 32 and 34. As shown in FIG. 2, endplate 150 is generally planar and has a configuration similar to frontface 24 of gear case housing 22. End plate 150 includes an aperture 152through which saw blade 38 is permitted to pass. In the embodimentillustrated, end plate 150 is attached to first and second forwardlyextending side wall members 32 and 34 by a plurality of threadedfasteners 154 adapted to pass through four apertures 156 provided in theend plate. Fasteners 154 are adapted to engage threaded holes 158located in boss portions 160 on each of the forwardly extending sidewalls members 32 and 34. In the embodiment illustrated, boss portions160 are located along the free ends of first and second forwardlyextending side wall members 32 and 34. It will be appreciated by thoseskilled in the art that end plate 150 can be alternatively attached toforwardly extending side wall members 32 and 34 in any of a number ofother well known manners. In this regard, it is anticipated that endplate 150 could alternatively be welded to forwardly extending sidewalls members 32 and 34.

Release lever 62 has a generally L-shaped cross section including afirst leg 170 and a second leg 172. The longitudinal length of releaselever 62 is sufficient to extend along the entire travel path of springclamp member 60 as drive shaft 30 is reciprocated. A longitudinallyextending aperture 174 passes through the length of release lever 62 atthe junction of first and second legs 170 and 172 and is adapted toreceive a pivot pin 176. Pivot pin 176 includes a first end 178 adaptedto engage an aperture 180 formed in front face 24 and a second end 182adapted to engage an aperture 184 located in end plate 150. Second end182 is of a reduced diameter so as to prevent forward translation of pin176.

As shown in FIGS. 11 and 12, release lever 62 is formed to include arecess or pocket 188 configured to accommodate a torsion spring 190.Torsion spring 190 functions to bias release lever 62 towards its firststable position (as shown in FIG. 11) and includes a central portionsurrounding an adjacent portion of pivot pin 176. Torsion spring 190also includes a fixed end 194 in engagement with a boss portion 196 ofrecess 188. Torsion spring 190 further includes a free end 198 adaptedto engage a stop pin 200 extending from front face 24 of gear casehousing 22. Stop pin extends into recess 180 to avoid interference withrelease lever 62.

As shown most clearly in FIGS. 11 and 12, second forwardly extendingwall member 34 is generally S-shaped in cross section and includes anupper segment 208 providing a stop surface 210 arranged to supportrelease lever 62. Upper segment 208 serves to prevent further rotationof release lever 62 in a counterclockwise direction as shown in FIGS. 11and 12. First leg 170 of release lever 62 transversely extends slightlybeyond an upper vertical segment 212 of second forwardly extending wallmember 34 so that the operator can grasp a free end 214 of first leg170.

First forwardly extending side wall member 32 is generally L-shaped incross-section and is formed along the perimeter of a correspondingportion of front face 24 of gear case housing 22. An upper segment 216of second forwardly extending side wall member 34 terminates at a stopsurface 218 for engaging release lever 62 when release lever 62 isrotated to its second stable position (as shown in FIG. 12).

Second leg 172 of release lever 62 includes an engagement surface 222adapted to contact spring tab portion 136 of spring clamp member 60. Asshown in FIG. 12, clockwise rotation of release lever 62 about alongitudinal pivot axis defined by pivot pin 176 results in contactbetween engagement surface 216 of second leg 172 and spring tab portion136 of spring clamp member 60. The length of second leg 172 issignificantly less than the length of first leg 170, thereby providing amechanical advantage for overcoming the biasing force exerted by springclamp member 60.

The pivot axis of release lever 62 defined by pivot pin 176 is disposedrelative to engagement surface 222 of second leg 172 so as to provide anover-centered relationship therebetween. As a result, as release lever62 approaches its second stable position (as shown in FIG. 12), theopposing biasing force of spring clamp member 60 urges release lever 62against stop surface 218 of first forwardly extending wall portion 32.

With particular reference to FIGS. 11 and 12, the operation of theclamping arrangement 56 of the present invention heretofore detailedwill now be described. Beginning with saw blade 38 operatively connectedto reciprocating drive shaft 30, release lever 62 is rotated in aclockwise direction from its first stable position (shown in FIG. 11) bymanual urging of first leg 170 to overcome the biasing force of torsionspring 190. Initial clockwise rotation causes second leg 172 of releaselever 62 to engage spring tab portion 136 of spring clamp member 62.

Continued clockwise rotation of release lever 62 serves to transverselydisplace spring tab portion 136 and to overcome the biasing force ofspring clamp member 62 by elastically deforming spring clamp member 60.More specifically, elastic displacement of spring tab portion 136creates a gap 224 between curvilinear central portion 120 of springclamp member 60 and saw blade 38. As release lever 62 approaches itssecond stable position, the over-centered relation between engagementsurface 222 of second leg 172 and the pivot axis defined by pivot pin176 causes the biasing force of spring clamp member 60 to further urgerelease lever 62 in a clockwise direction against stop surface 218. Atthis point, release lever 62 will stay in its second stable positionuntil urged in the direction of its first stable position. As a result,both of the operator' hands are free for handling replacement of sawblade 38 or other necessary tasks.

Saw blade 38 can now be removed from power tool 10 and a new blade canbe inserted into gap 224 between spring clamp member 60 andreciprocating drive shaft 30. Upper edge 94 of saw blade 38 is locatedin channel 90 and aperture 48 is positioned over drive pin 42. Operatinginterconnection between saw blade 38 and reciprocating drive shaft 30 isestablished by manual urging of release lever 62 in a counterclockwisedirection. Following initial counterclockwise movement of lever 62, thebiasing force of spring clamp member 60 urges release lever 62 to itsfirst stable position.

Turning now to FIGS. 13-19 of the drawings, a saw blade clampingarrangement 56' constructed in accordance with the second preferredembodiment of the present invention will now be described. In thissecond embodiment, components similar to those identified with respectto the first embodiment will be designated in the drawings withcorresponding reference numerals. As with the first preferredembodiment, saw blade clamping arrangement 56' is operative for use withpower tool 10 such as a reciprocating saw or other tool including areciprocating drive shaft 30.

As with the first preferred embodiment of the present invention, the sawblade clamping arrangement 56' of the second preferred embodimentincludes a clamp support member 58, a biasing member 60 and an actuationmember 62. The saw blade clamping arrangement 56' of the secondpreferred embodiment departs from the first preferred embodiment in thatit additionally incorporates a locking member 230 operative toselectively engage saw blade 38 and interconnect saw blade 38 to driveshaft 30. The remainder of this detailed description of the secondpreferred embodiment will address departures in construction andfunction of the second preferred embodiment from the first preferredembodiment.

As shown in FIG. 13, drive shaft 30 of the second preferred embodimentis generally cylindrical and includes an open distal end 232 forreceiving a first end 234 of clamp support member 58. In the exemplaryembodiment illustrated, first end 234 of clamp support member 58 anddrive shaft 30 are interconnected by pin 68 which engages cooperatingapertures 235 located in first end 234 and shaft 30. However, it will beappreciated by those skilled in the art that any suitable manner may beutilized to operatively interconnect clamp support member 58 with driveshaft 30. For example, clamp support member 58 and shaft 30 mayalternatively be press fit together and brazed.

With reference to FIGS. 14 and 15, clamp support member 58 is shown toinclude a generally rectangular channel 236 partially extendinglongitudinally therethrough. Rectangular channel 236 is open adjacent asecond end 238, or distal end, of clamp support member 58 and isconfigured to receive mounting portion 46 of saw blade 38. Clamp supportmember 58 further includes a transversely extending recess 240 having agenerally conical portion 242 and a reduced diameter cylindrical portion246. Reduced diameter cylindrical portion 246 is arranged to align withaperture 48 in mounting portion 46 of saw blade 38 upon insertion of sawblade 38 into channel 236. Conical portion 242 is partially defined byan upwardly extending cylindrical flange 248. As will become apparentbelow, recess 240 is configured to cooperatively receive locking member230.

With continued reference to FIG. 13 and additional reference to FIG. 16,locking member 230 is shown to include a generally conical portion 250configured to cooperate with conical portion 242 of recess 240. In asimilar manner, locking member 230 includes a generally cylindricalportion 252 adapted for insertion into cylindrical portion 246 of recess240. When locking member 230 is seated into recess 240 of clamp supportmember 58, cylindrical portion 252 intersects rectangular channel 236and engages aperture 48 in mounting portion 46 of saw blade 38, therebyoperatively interconnecting saw blade 38 with clamp support member 58.Locking member 230 is shown to further include a head 254 interconnectedto conical portion 250 through a reduced diameter portion 256.

With reference now to FIGS. 13 and 17, biasing member 60 of the secondpreferred embodiment will now be described. As with the first preferredembodiment, biasing member 60 of the second preferred embodiment is aspring clamp member 60 adapted to be directly carried by clamp supportmember 58 for movement with drive shaft 30. Spring clamp member 60includes a first end 122 displaceable by actuation member 62 and asecond end 124 constrained with respect to clamp support member 58.Second end 124 is constrained within longitudinal channel 108 of clampsupport member 58. Spring clamp member 60 normally functions to biaslocking member 230 to a seated position within recess 240 of clampsupport member 58 and thereby operatively interconnect clamp supportmember 58 and saw blade 38.

As most clearly shown in FIG. 17, spring clamp member 60 includes anaperture 258 disposed adjacent first end 122. Aperture 258 includes anelongated portion 260 interconnected to a circular portion 262. In use,head 250 of locking member 230 is inserted through circular portion 262of aperture 258 and reduced diameter portion 256 of locking member 230is positioned within elongated portion 260. As first end 122 of springclamp member 60 is deflected by actuation member 62, reduced diameterportion 256 of locking member 230 is permitted to translate withinelongated portion 260.

As with the first preferred embodiment, the release lever 62 of thesecond preferred embodiment is pivotally interconnected to housing 18for movement between a first position and a second position. In thisregard, pivot pin 176 passes through longitudinally extending aperture174. First end 182 engages aperture 184 formed in cover plate 150.Similarly, second end 178 engages aperture 180.

In the first position (as shown in FIG. 19), release lever 62 is spacedapart from spring clamp member 60 and does not reciprocate with driveshaft 30. Free end 214 of release lever 62 abuts a lip 262 formed withhousing 18 to prevent further rotation of release lever 62 in aclockwise direction as shown in the drawings. In its second position (asshown in FIG. 18), release lever 62 displaces first end 122 of springclamp member 60, thereby partially removing locking member 230 fromrecess 240. As a result, cylindrical portion 252 is withdrawn fromchannel 236 and aperture 48 of saw blade 38, thereby permitting removalof saw blade 38.

Turning now to FIGS. 20-31 of the drawings, a saw blade clampingarrangement 56" constructed in accordance with the third preferredembodiment of the present invention will now be described. Again,components similar to those identified with respect to the firstembodiment will be designated in the drawings with correspondingreference numerals. As with the first and second preferred embodiments,saw blade clamping arrangement 56" is operative for use with power tool10 such as reciprocating saw or other tool including a reciprocatingdrive shaft 30.

As with the first preferred embodiment of the present invention, sawblade clamping arrangement 56" of the third preferred embodimentincludes a support member 58, a biasing member 60 and an actuationmember 62. Saw blade clamping arrangement 56" of the third preferredembodiment departs from the first preferred embodiment in that itadditionally incorporates a locking member 310 operatively interconnectsaw blade 38 to drive shaft 30, a control member 312 operative todisplace locking member 310, and a collar 314 movably supporting controlmember 312. The remainder of this detailed description will addressdepartures in construction and function of the third preferredembodiment from the prior embodiments.

As with the second preferred embodiment, drive shaft 30 of the thirdpreferred embodiment is generally cylindrical and includes an opendistal end 232 for receiving a first end 234 of support member 58.Preferably, first end 234 of support member 58 and shaft 30 arepress-fit together and brazed. Alternatively, it will be appreciated bythose skilled in the art that any suitable manner may be utilized tooperatively interconnect support member 58 with drive shaft 30.

With specific reference to FIGS. 25 and 26, clamp support member 58 oftool 56 is shown to include a pair of spaced apart legs 316. A generallyrectangular channel 318 (best shown in FIG. 24) is partially defined bythe pair of legs 316 and extends substantially the entire length of legs316 and is adapted to receive mounting portion 46 of saw blade 38.Support member 58 further includes a transversely extending elongatedhole 320. Aperture 320 extends through a first leg 316a and intersectsrectangular channel 318. Upon insertion of saw blade 38 into channel318, aperture 320 is substantially aligned with aperture 48 in mountingportion 46 of saw blade 38. As will become apparent immediately below,aperture 320 is configured to receive locking member 310. Locking member310 of the third preferred embodiment is shown to preferably comprise aspherical bearing 310. Bearing 310 has a diameter slightly smaller thanthe width of elongated hole 320. The elongated configuration of the holeallows the bearing 310 to float and easily locate hole 48 in saw blade38.

With reference now to FIGS. 21, 22, 27 and 28, control member 312 of thethird preferred embodiment will now be described. Control member 312 isinterconnected to support member 58 so as to be linearly translatablewith respect thereto. In the embodiment illustrated, control member 312is linearly translatable in a direction substantially perpendicular tothe direction of reciprocal motion of drive shaft 30 between a firstposition and a second position. As will be discussed further below,control member 312 is operatively retained relative to support member 58through collar 314. Control member 312 is operative for selectivelyurging bearing 310 into engagement with saw blade 38 to therebyoperatively engage saw blade 38 with drive shaft 30. More particularly,in a first position, as shown specifically in FIG. 21, control member312 urges bearing 310 into engagement with saw blade 38. In this firstposition, bearing 310 is partially inserted into aperture 46 from afirst side of saw blade 38. In its second position, as shown in FIG. 22,control member 312 permits bearing 310 to be displaced from a positionengaged with aperture 46 of saw blade 38, thereby permitting removal andreplacement of saw blade 38.

With continued reference to FIG. 27 and the cross-sectional view of FIG.28, control member 312 is shown to include a channel 326 for at leastpartially receiving bearing 310. The channel 326 includes a dish-shapedpocket 328 and a concavely curved trough 330. Trough 330 is defined by acamming surface which is angled such that trough 330 is most shallow ata point displaced from cavity 328. When control member 312 is in itssecond position (as shown in FIG. 22), locking member 310 issubstantially centered within cavity 328 of channel 326. As a result,bearing 310 can be displaced from a position in which it is engaged withaperture 46 of saw blade 38. As control member 312 is moved from itssecond position to its first position, bearing 310 rides along trough330. Given the angular orientation of trough 330, bearing 310 isresultantly forced toward rectangular channel 318 and into engagementwith aperture 46 of saw blade 38.

With reference to FIGS. 29-31, collar 314 of the third preferredembodiment of the present invention will now be described. As notedabove, collar 314 functions to interconnect control member 312 withsupport member 58, and in turn drive shaft 30. Collar 314 includes amain body portion 332 which defines a central aperture 334 adapted toreceive the pair of legs 316 of the support member 58. As a result,collar 314 effectively circumferentially surrounds support member 58. Acotter pin 336 passes through a hole 338 in main body portion 332 and acorresponding hole 340 in support member 58 to thereby releasablyinterconnect 314 and support member 58.

As shown specifically in FIG. 30, collar 314 defines a generallyT-shaped channel 339 adapted to slidingly receive control member 312.More particular, T-shaped channel 339 includes a vertically orientedportion 340 and a horizontally oriented portion 342. Vertically orientedportion 340 is specifically adapted to receive a pair of outwardlyextending flanges 344 which are integrally formed with control member312. A flange 346 extends through horizontally oriented portion 342 andslightly beyond.

It will be appreciated that in certain applications it may be desirableto provide the collar 314 in two components. For example, atwo-component collar may provide manufacturing advantages. Withreference to FIGS. 32 and 33, an alternative two-piece collar 314 foruse with the saw blade clamping arrangement 56" of the third preferredembodiment. The collar 314 is shown to include two components, namely.An outer member 350 is shown in FIGS. 32A and 32B. An inner member 352is shown in FIGS. 33A and 33B. The outer and inner members 350 and 352cooperate to accomplish the functions on the collar 314 discussed above.

In the embodiment illustrated, biasing member 60 comprises a coil spring60 which circumferentially surrounds support member 58. As shown in FIG.23, a first end 350 of coil spring 60 engages an aperture 352 formed insupport member 58. A second end 354 of coil spring 60 and aperture 356formed in flange 346 below control member 312. Coil spring 60 functionsto normally bias control member 312 towards its first position (as shownin FIG. 21) in which bearing 310 is forced into engagement with aperture46 of saw blade 38.

Referring now to FIGS. 20-22, the release lever of the third preferredembodiment is shown pivotally interconnected to housing 18 for movementbetween a first position (as shown in FIG. 21) and a second position (asshown in FIG. 22). In this regard, a pivot pin 176 passes through alongitudinally aperture in release lever 62. First end 182 of pivot pin186 engages apertures 184 formed in cover plate 150. Second end 178 ofpivot pin 176 engages aperture 180. Alternatively, it will beappreciated by those skilled in the art that release lever 62 can beintegrally formed to include cylindrical portions extending in oppositedirections and effectively replacing pivot pin 176.

In the first position, release lever 62 is spaced apart from flange 346of control member 312. It will be appreciated that release lever 62 doesnot reciprocate with drive shaft 30. In its second position, releaselever 62 displaces control member 312 to its second position, therebypermitting removal and replacement of saw blade 38 in the mannerdiscussed above. In the preferred embodiment, release lever 62 of thethird preferred embodiment is mounted to tool 10 such that aninterference fit is established so as to maintain release lever 62 inits release position. Alternatively, release lever 62 may be mounted totool 10 such that its second position (as shown in FIG. 22) is anover-centered position.

In the exemplary embodiment illustrated, the saw blade clampingarrangement 56" of the third preferred embodiment is shown to include alocating pin 360 which extends into the longitudinal opening of thesupport member 58 and is adapted to engage the aperture 46 of the sawblade 38 from a second side of the saw blade 38. Spherical bearing 310and locating pin 360 cooperate to prevent inadvertent removal of sawblade 38 from the longitudinal slot. In this regard, locating pin 360prevents spherical bearing 310 from being pushed out of aperture 46 whensaw blade 38 is under severe loads. Locating pin 360 is adapted to seatin aperture 46 of blade 38 and accordingly serves to further lock blade38 in place. The diameter of locating pin 360 is smaller than aperture46 of saw blade 38, thereby permitting spherical bearing 310 and thespring force applied to spherical bearing 310 to locate blade 38 withinclamp 58. Specifically, to prevent release of blade 38 from clamp 58when spherical bearing 310 tends to slide out of the longitudinal bladeopening slot, the sidewall of aperture 46 of saw blade 38 engageslocating pin 360 and blade 38 is retained within clamp 58.

While the above description constitutes three preferred embodiments ofthe invention, it will be appreciated that the invention is susceptibleto modification, variation, and change without departing from the properscope or fair meaning of the accompanying claims. For example, it willbe understood that the teachings of the present invention are directlyapplicable to other power tools having reciprocating drive shafts,including but not limited to jigsaws.

What is claimed is:
 1. A saw blade clamping arrangement for a power toolincluding a housing, a drive shaft mounted for reciprocating motion in alongitudinal direction relative to the housing, and a saw blade havingan aperture releasably interconnected with the drive shaft, the sawblade clamping arrangement comprising:a support member carried by thedrive shaft for movement therewith, said support member at leastpartially defining a longitudinal slot for receiving the saw blade; alocating pin extending into said longitudinal slot and adapted forinsertion into the aperture from a first side of the saw blade; alocking member operative for selectively engaging said saw blade withsaid drive shaft, said locking member movable to a locking position inwhich said locking member is partially inserted into the aperture from asecond side of the saw blade; a linearly movable element translatablefrom a first position to a second position for moving said lockingmember to said locking position; and an actuation member attached to thepower tool, said actuation member operative to selectively move saidlinearly movable element between said first and second positions;whereby said locking member and said locating pin cooperate to preventinadvertent removal of the saw blade from said longitudinal slot.
 2. Theblade clamping arrangement of claim 1, wherein said locking member is aspherical bearing.
 3. The blade clamping arrangement of claim 1, whereinsaid actuation member is a release lever longitudinally fixed withrespect to the housing, said release lever being normally spaced apartfrom said linearly movable element.
 4. The blade clamping arrangement ofclaim 3, wherein said release lever is mounted for pivotal movementabout a pivot axis spaced apart from and parallel to the drive shaft. 5.The blade clamping arrangement of claim 1, wherein said linearly movableelement defines a camming surface for urging said locking member intoengagement with said saw blade when said linearly movable element istranslated from said second position to said first position.
 6. A powerreciprocating saw comprising:a housing; a drive shaft mounted to thereciprocating saw for reciprocating movement in a longitudinaldirection; a saw blade; and a clamping arrangement for selectivelymounting said saw blade to said drive shaft, said clamping arrangementincluding:a support member carried by the drive shaft for movementtherewith, said support member at least partially defining alongitudinal slot for receiving the saw blade; a locating pin extendinginto said longitudinal slot and adapted for insertion into the aperturefrom a first side of the saw blade; a locking member operative forselectively engaging said saw blade with said drive shaft, said lockingmember movable to a locking position in which said locking member ispartially inserted into the aperture for a second side of the saw blade;a control member translatable from a first position to a second positionfor moving said locking member to said locking position; and anactuation member attached to the power tool, said actuation memberoperative to selectively move sand control member between said first andsecond positions; whereby said locking member and said locating pincooperate to prevent inadvertent removal of the saw blade from saidlongitudinal slot.
 7. The power reciprocating saw of claim 6, whereinsaid locking member comprises a spherical bearing.
 8. The powerreciprocating saw of claim 6, wherein said actuation member islongitudinally fixed with respect to said housing, said actuation membermoveable between a clamping position in which said control member istranslated to said first position for urging said locking member intooperative engagement with said saw blade and a release position in whichsaid control member is translated to said second position for permittingdisplacement of said locking member from said saw blade.
 9. The powerreciprocating saw of claim 6, further comprising a biasing member forbiasing said control member to said first position.
 10. The powerreciprocating saw of claim 6, wherein said actuation member is a releaselever mounted for pivotal movement between said clamping position andsaid release position.
 11. The power reciprocating saw of claim 10,wherein said release lever is mounted for pivotal movement about a pivotaxis parallel to and spaced apart from said saw blade.
 12. The bladeclamping arrangement of claim 6, wherein said control member includes acamming surface for urging said locking member into engagement with saidsaw blade.
 13. A power reciprocating saw comprising:a gear case housing;a drive shaft mounted to the reciprocating saw for reciprocating motionrelative to said gear case housing in a longitudinal direction; a sawblade having an aperture; and a clamping arrangement for mounting saidsaw blade to said drive shaft, said clamping arrangement including:(a) asupport member interconnected with said drive shaft for movementtherewith, said support member at least partially defining alongitudinal slot for receiving said saw blade and a transverselydisposed aperture intersecting said longitudinal slot; (b) a locatingpin extending into said longitudinal slot and adapted for insertion intothe aperture from a first side of the saw blade; (c) a control memberinterconnected to said support member, said control member linearlytranslatable in a direction substantially perpendicular to saidlongitudinal direction between a first position and a second position;(d) a spherical bearing adapted for partial insertion into said aperturefrom a second side of said saw blade in response to movement of saidcontrol member between said first position and said second position tooperatively interconnect said saw blade relative to said drive shaft,said spherical bearing extending at least partially into saidtransversely disposed aperture of said support member; (d) a releaselever pivotally attached to said housing for pivotal movement between aclamping position in which said control member is in said first positionand said bearing is engaged with said saw blade and a release positionin which said control member is in said second position and saidspherical bearing is permitted to be displaced from said saw blade. 14.The power reciprocating saw of claim 13, further including a collarreleasably attached to and circumferentially surrounding said clampsupport member, said control member movably attached to said collar. 15.The power reciprocating saw of claim 14, wherein said control memberdefines a camming surface for urging said bearing into engagement withsaid saw blade when said control member is translated from said secondposition to said first position.
 16. The power reciprocating saw ofclaim 13, further comprising a biasing member for biasing said controlmember to said first position.
 17. A saw blade clamping arrangement fora power tool including a housing, a drive shaft mounted forreciprocating motion in a longitudinal direction relative to thehousing, and a saw blade having an aperture releasably interconnectedwith the drive shaft, the saw blade clamping arrangement comprising:asupport member carried by the drive shaft for movement therewith, saidsupport member at least partially defining a longitudinal slot forreceiving the saw blade; a locating pin fixedly carried by the supportmember and extending into said longitudinal slot and adapted forinsertion into the aperture from a first side of the saw blade; and alocking member operative for selectively engaging said saw blade withsaid drive shaft, said locking member movable to a locking position inwhich said locking member is partially inserted into the aperture from asecond side of the saw blade; whereby said locking member and saidlocating pin cooperate to prevent inadvertent removal of the saw bladefrom said longitudinal slot.
 18. The blade clamping arrangement of claim17, wherein said locking member is a spherical bearing.
 19. The bladeclamping arrangement of claim 18, wherein said clamping arrangementfurther comprises a linearly movable element translatable from a firstposition to a second position for moving said locking member to saidlocking position.
 20. The blade clamping arrangement of claim 19,wherein said clamping arrangement further comprises an actuation memberattached to the power tool, said actuation member operative toselectively move said linearly movable element between said first andsecond positions.
 21. The blade clamping arrangement of claim 20,wherein said actuation member is a release lever longitudinally fixedwith respect to the housing, said release lever being normally spacedapart from said linearly movable element.
 22. The blade clampingarrangement of claim 21, wherein said release lever is mounted forpivotal movement about a pivot axis spaced apart from and parallel tothe drive shaft.
 23. The blade clamping arrangement of claim 17, whereinsaid linearly movable element defines a camming surface for urging saidlocking member into engagement with said saw blade when said linearlymovable element is translated from said second position to said firstposition.